A file of signals intelligence reports, messages, and correspondence issued by the Government Code and Cypher School and sent by the head ('C') of the Secret Intelligence Service (MI6) to the Prime Minister, Winston Churchill. This file includes the following correspondence: from the Japanese minister in Lisbon, on U.S. naval vessels south east of Africa, on March 14; that a Japanese firm in Saigon is to build wooden sailing ships, from March 17; that the Japanese minister in Berne was instructed to ask the Swiss to enquire about the crew of a missing submarine, on March 19; from the Turkish ambassador in Berlin on the German view of Bulgarian policy, on March 17; from the Italian minister in Bucharest on the Russian offensive, on March 15; from the Japanese minister in Stockholm on German unease at Japanese successes, on March 14; and Tokyo denies British allegations of atrocities in Hong Kong, on March 15.